1. Field of the Invention
The present general inventive concept relates to a rotary compressor, and more particularly, to a rotary compressor with a variable capacity.
2. Description of the Related Art
A conventional cooling apparatus applied to an air conditioner or a refrigerator employs a variable capacity rotary compressor having a variable cooling ability for optimum cooling, and a variable coolant compressing ability for energy saving.
As disclosed in Korean Patent First Publication No. 2004-21140, the variable capacity rotary compressor includes a housing formed with a compression chamber, a rotating shaft having an eccentric part rotating in the compression chamber, a roller rotatably disposed to an outer surface of the eccentric part so that an outer surface of the roller is in contact with an inner surface of the compression chamber, a vane disposed in the housing to reciprocate in a radial direction of the compression chamber with a front end part of the vane being in contact with an outer surface of the roller when the roller rotates, and a restricting means restricting the vane.
The restricting means includes a cylinder coupled to an outer side of the housing to restrict the vane by pressure of an inlet and an outlet of the rotary compressor, a piston disposed in the cylinder to reciprocate in an actuating direction of the vane and accommodating a rear end part of the vane to reciprocate in an inner part of the piston, a first channel communicating with an inner part of the cylinder, a second channel connecting the outlet of the rotary compressor and the first channel, a third channel connecting the inlet of the rotary compressor and the first channel, and a channel changing valve disposed at a junction where the first, second, and third channels are connected.
Here, the cylinder forms an extended space having a width relatively greater than the width of the vane to a rear end area of a vane coupling groove in which the vane is accommodated. By controlling pressure of the extended space, reciprocating of the vane is controlled.
However, in the conventional rotary compressor, since the extended space formed to a rear end area of the vane has a width excessively greater than the width of the vane, a large amount of compressed media is required to actuate the vane. Accordingly, an actuating response speed of the vane is deteriorated, and an actuating noise of the vane is generated.